运行下面程序，结果如图表示。(此程序是Logo语言编写)
TO ZFX
REPEAT 4[FD ______ RT 90]
PU FD 25 RT 90 FD 25 LT 90 ______
END
TO TU
REPEAT 4[REPEAT ______ [ZFX] RT ______
REPEAT 4[ZFX]RT ______]
END